Movable face support for use in mines



July 4, 1967 F. H. CREUELS ETAL 3,328,965

MOVABLE FACE SUPPORT FOR USE IN MINES 6 Sheets-Sheet 1 Filed March 25, 1964 July 4, 1967 F. H. CREUELS ETAL 3,3 8,966

MOVABLE FACE SUFPORT FOR USE IN MINES Filed March 25, 1964 s Sheets-Sheet 2 y 1967 F. H. CEUELS ETAL 3,

MOVABLE FACE SUPPORT FOR USE IN MINES Filed March 25, 1964 t Y 6 Sheets-Sheet Z5 J l I 1 8 FIG.4 c I a f D E 8 c g r rL tal July 4, 1967. 'F'. H. CREUELS ETAL. 3,328,966

MOVABLE FACE SUPPORT FOR USE IN MINES Filed March 25, 1964 6 Sheets-Sheet 4 I. I 7) k PIC-3.6

y 4, 1967 F. H. CREUELS ETAL 3,328,966

MOVABLE FACE SUPPORT FOR USE IN MINES Filed March 25, 1964 6 Sheets-Sheet 5 Q 2 8 2M 26 2 4 I".

I I 5 I 1 5 [I i 14 l 22 I :1 l 13 n 21 9 II 52 6' 1' I 12 27 22' E r G ,21 62 I FIG] ago/HM 771M WTMWV United States Patent 3,328,966 MOVABLE FACE SUPPORT FOR USE IN MINES Frans H. Creuels, Hoensbroek, and Johannes M. Hermes, Heerlen, Netherlands, assignors to Stamicarbon N.V., Heerlen, Netherlands Filed Mar. 25, 1964, Ser. No. 354,667 7 Claims priority, application Netherlands, Mar. 29, 1963, 290,947; Nov. 5, 1963, 300,145; Nov. 8, 1963, 300,304 17 Claims. (Cl. 61-45) This invention relates to mine face supports.

More particularly the invention relates to so-called walking face supports comprising a guide structure which in use is coupled to a face conveyor and along which the props are bodily slidable. The guide structure of such a support can be periodically drawn towards the conveyor to keep pace withits advance as face Winning proceds, and different props can be slid forward at diiferent times so that the roof support is never entirely released.

The advance of the guide structure is under power, the reaction force being sustained by the conveyor so that the guide structure is drawn towards its point of connection to the conveyor. Diflieulties are encountered with known support constructions if the supports get out of line with their points of connection to the conveyor or if the direction of advance of the face or a face section changes, because the supports cannot turn in the horizontal plane while supporting the roof.

A face support which is directionally self-adjusting is provided by the present invention which broadly defined comprises a guide structure having a haulage gear which can be connected to a face conveyor, runners displaceable along parallel tracks on the guide structure, independently releasable prop units pivotally connected to the runners so that the prop units can swing independently in the horizontal plane relative to the guide structure, and spring members which afford elastic resistance to pivotal motion of the prop units in either direction from a centralised position.

In walking face supports, the props are usually in independently releasable units of two or more props, the props of each unit having an associated roof girder or roof girders and a base or bases forming with the props a kind of frame. The prop units of supports according to the invention may be and preferably are of this kind (and such units may each comprise one or more than one such frame). However this is not essential and a prop unit need not have more than one prop.

If a support according to the invention happens to be out of line with the direction of advance of its anchorage point on a conveyor one or more spring members allow the guide structure to turn in the horizontal plane during (and if necessary before) advance of the guide structure. During advance of the guide structure, at least one prop unit remains clamped against the roof, and when this prop unit is in its turn released and advanced the'appertaining spring member or members recentralise the unit about its pivot.

It is explained-that the term spring member is used to include not only helical and leaf springs but rubber blocks, air springs or cushions, hydraulic cylinder and piston units and any other functionally equivalent means.

The runners to which the prop units are pivoted may have any kind of engagement with the guide structure which permits them to move to and fro therealong. In

3,328,966 Patented July 4, 1967 the embodiments of the invention hereinafter described in detail the runners are in the form of slides and are referred to as such.

The spring system is preferably so arranged that the restoration of a prop unit to centralised position does not involve re-energising a spring at one side of the pivot. This can be achieved by avoiding any preloading of the springs in the normal or centralised position of the prop units but preferably it is achieved by incorporating stop devices which hold each spring member pre-stressed and shield the appertaining prop units from the force stored in the spring member until this member is further energised by movement of a prop unit. In that case the spring members are capable of exerting large restorative forces on the prop units for comparatively small displacements.

If, by the provision of stop means aforesaid or otherwise, the spring members exert no force on the prop units so long as they are centralised then it follows that the spring members will not impose any material resistance to the motion of the runners even if the spring members bear directly against the guide structure. Such resistance will only arise if the runners are displaced while the prop units are out of centralised position.

As will hereafter be exemplified, it is possible to arrange the spring members so that they are operative as between the prop units and their runners. In that case the advantage is achieved that in no position of a prop unit does its spring member or members give rise to fric tional resistance to displacement of the associated runner or runners along the guide structure. Moreover, this arrangement of the spring members permits them to bear on the prop units at greater distances from their pivots.

Preferably leaf or laminated springs are used with their central portions bearing on the runners and their ends bearing against the prop units.

The haulage gear of the guide structure may comprise a hydraulic piston and cylinder unit. This unit may be directly coupled through the piston rod with a conveyor section. In virtue of the provision of the spring members such haulage gear will not be subjected to such injurious abaxial forces as would otherwise arise. Nevertheless it is preferable to connect the haulage gear to the conveyor by a flexible rope, chain or other tie and to support the piston rod in an axial guide and/ or to run the tie through a central guide (e.g., between a pair of rollers) on the guide structure.

The haulage gear for the guide structure may also serve for advancing the prop units. For example, the prop units may be connected to a common flexible tie or to different flexible ties displaceable by the aforesaid haulage gear. It is possible as will hereafter be exemplified to arrange the system so that a given stroke of a piston and cylinder unit advances the guide structure over a given distance and simultaneously advances one of the prop units over twice that distance.

Various embodiments of the invention, selected by way of example, will now be described with reference to the accompanying diagrammatic drawings in which:

FIGURE 1 is a plan view of a movable face support according to the invention;

FIGURE 2 is a longitudinal section of the support;

FIGURE 3 is a cross-section of the lower part of the support;

FIGURE 4 and FIGURE 5 give a schematic representation of the movement of the support, and

FIGURES 6, 7 and 8 are plan views of modified embodiments.

The movable face support shown in the FIGURES 1-3 consists of two supporting frames 1 and 1', constituting a pair of prop units or prop means, built up of hydraulic props 23 and 2'-3, respectively, roof girders 4 (one to each prop), and bases 5 and 5'.

The bases 5, 5 on the one hand and bases 5, 5' on the other hand are connected to each other by means of two spaced, resilient strips 6 and 6', respectively, so that the props of each frame are capable of articulating in the vertical plane so that they can adapt themselves to differences in height in the floor of the seam. A flexible coupling member 7 is provided between each pair of aligned roof girders to enable them to adapt themselves to irregularities in the roof.

Each prop means considered in its entirety is of a generally horizontally elongated configuration, as can be seen from FIGURE 2. The terms horizontal and vertical and derivatives thereof are not used herein in their absolute sense :but are intended to be relative terms having reference to the extent of the mine floor and roof and the perpendicular extent therebetween, it being understood that the extent of a mine floor or roof is frequently inclined with respect to true horizontal.

Between the frames 1 and 1 a central guide structure 8 is mounted, which is provided with guides 9 and 9'. A hydraulic cylinder 10 is fastened to the said structure by means of a pin 11 and supported on it by means of a collar 12. At its end 14, the piston rod 13 is provided with a wheel 15, over which a rope 16 is passed. One end of the rope is connected to the face conveyor 18 at 17, the other end being fastened to the guide structure at 19. Owing to the cylinder being coupled to the conveyor in this way, the guide structure can be moved over a distance which is twice as long as the stroke of the cylinder. The rope 16 is passed between two rollers 20 provided at the end of the central structure, so that no transverse forces can act on the cylinder rod even if the portion of the rope 16 extending up to the conveyor is not in line with the piston rod.

Between the props of the supporting frames 1 and 1' slides 21 and 21', respectively, are fitted, which are capable of pivoting relatively to the frames 1, 1' about pins 22 and 22', respectively, which run parallel to the props. The slides are slidable along the guides 9 and 9' and are connected to each other by means of a rope 23, which passes over wheels 24 and 25 provided at the front of the guide structures. On either side of the slides the connecting strips 6 are provided with spring loaded plungers 26 and 27, and 26' and 27, respectively, which elastically press against the central guide structure. Instead of spring loaded plungers hydraulic or pneumatic pistons or springs (e.g. cup springs) bearing directly against the guide structure may be empolyed.

In FIGURE 1, frame 1 is shown in its foremost position, frame 1 in its hindmost position. When the support is installed at a coal face and the coal face has advanced so far that frame 1' can be shifted, the props 2' and 3' are released, so that the roof girders 4 get clear of the roof. A pressure medium is supplied to cylinder 10, as a result of which the piston rod 13 moves inwards and pulls forward the guide structure 8 and the cylinder by means of the rope 16 fastened to the conveyor 18 and the guide structure. The distance over which the frame is moved is twice as long as the stroke of the piston.

When the guide structure is shifted, the wheels 24 and 25 are also advanced. As frame 1 is anchored between the roof and the floor of the face gallery, frame 1' is pulled forward by the rope 23 passing over the wheels 24 and 25, over a distance which is twice as large as the movement of the guide structure and, consequently, four times as long as the stroke of the piston. Frame 1', which was at first behind frame 1 at a distance twice as long as the stroke of the piston, is now at the same distance in front of this frame. After the shifting, frame 1' is reset by admitting liquid pressure medium into the hydraulic props 2' and 3'. The stroke of the piston is preferably made somewhat longer than would be necessary to realize the desired step length, so that both frames can be drawn up to the conveyor, if desired.

When the guide structure 8 is moved, its guide 9 slides within the slide 21 and relative to the contracting plungers 26 and 27 of the fixed frame 1. At the same time, the slide 21' and the plungers 26 and 27' of the released frame 1 slide along the guide 9'. If the support is in the correct position relative to its points of connection to the conveyor, in which case the point 17 at which the rope 16 is fastened to the conveyor is in line with the center line of the cylinder 10 and this center line is parallel with the direction of advance of the conveyor, all the elements of the support move parallel to this line.

This is not the case, however, if the support forms an angle with the direction in which the coal face advances, or if (e.g. due to slope of the seam) the support has shifted with respect to the point of connection 17 in a direction parallel to the longitudinal axis of the conveyor.

In the position shown in FIGURE 4a the support forms an angle with the direction in which the coal face advances (indicated by the arrow). To shift the hindmost frame 1', the props 2 and 3 are released and pressure is admitted to the hydraulic cylinder 10. The guide structure 8 slides within the slide 21 and becomes so disposed that the point of connection 17 is nearer to the center line of the cylinder. The angle between the guide structure 8 and the direction indicated by the arrow will now be smaller. As the structure 8 advances the slide 21 turns with the structure about shaft 22, so that the plunger 26 becomes slightly depressed against its spring and the plunger 27 advances further from its housing. The frame 1' slides forward along the guide structure and is maintained parallel to the guide structure by the spring plungers 26 and 27. When the said frame is in its final position, it is reset (FIGURE 4b).

When the coal face has advanced over a distance equal to the step length of the support, and the conveyor 18 has been pushed forward over the said distance by a pushing cylinder (not shown in the drawing), the props 2 and 3 are released and pressure is again admitted to the hydraulic cylinder 10 for advancing the guide structure 8. The structure 8 and the frame 1 move in the direction of the conveyor, the plungers 26 and 27 exerting such a couple on the released frame that the latter is restored to a centralised position about its pivot, i.e. parallel to the guide structure 8. When the said frame 1 is in its final position (FIGURE 4c), the props 2 and 3 are reset. It will be seen that the original angular deviation (FIGURE 4a) has already been largely corrected.

As a rule, small deviations are corrected already after a single step, whereas larger deviations are eliminated after two or more steps. In this connection it should be noted, however, that, owing to the self-correcting action of the support, it is unlikely that large deviations will occur. When the supports are being installed at a coal face, they need not be disposed very accurately, as they correct any deviations themselves when being advanced. Consequently, the frames can be installed more rapidly.

In the position shown in FIGURE 5a the support has shifted with respect to the point of connection 17 in a direction parallel to the longitudinal axis of the conveyor. Such a situation may arise e.g. due to the fact that the support has slid down in a sloping seam towards the lower end of the face, or to the fact that a conveyor which had slid down has been drawn up again. To move the support, the props 2' and 3' of the hindmost frame 1 are released and pressure is admitted to the hydraulic cylinder 10. As a result, the structure 8 is advanced in the direction of the conveyor and in course of this advance the structure turns in the horizontal plane until the centre line of the cylinder is directed towards the point of connection 17.

The released frame 1' is meanwhile kept in a position parallel to the guide structure by the spring plungers 26' and 27, and the frame is fixed again between roof and floor as soon as it has taken up its final position. Due to the turning of the guide structure, the slide 21 pivots on the pin 22 through a certain angle (FIGURE 5b), so that the plunger 26 between the fixed frame 1 and the guide structure becomes slightly extended, whereas the plunger 27 becomes slightly depressed.

When the coal face has advanced over a distance equal to the step length of the support and the conveyor 18 has been pushed forward over the said distance, the props 2 and 3 of the frame 1 are released and pressure is again admitted to the hydraulic cylinder. As a result, the structure 8 and the frame 1 are shifted in the direction of the conveyor and the plunger 27 turns the frame 1 about the shaft 22 until the said frame is again parallel to the structure. After the frame 1 has been shifted, the props 2 and 3 are clamped between the roof and the floor again (FIG- URE 5c). It will be seen that the-bodily position of the support in a direction parallel with the conveyor has been corrected but the angular position of the support is not yet quite correct.

When the support is shifted further, the angular deviation will become corrected, as has been described above with reference to the FIGURES 4ac.

The construction of the support ensures that the support follows the point of connection 17, which, irrespective of the angles between the face gallery and the transport roadways, always advances in line with the direction of coal getting. The pivotable guide members 21 and 21' enable the guide structure to direct itself towards this point of connection. The resilient connection between the frames and the guide structure causes the frames to take up a position parallel to the central structure when the frames are released.

In the embodiment shown in FIGURE 6 there are four frames each comprising two props. The frame comprising props 28, 29 moves in unison with the frames comprising props 30, 31, and the other two frames, comprising 28', 29' and 30', 31' respectively are likewise interconnected. The props of the individual frames are connected by beams 32, 33, 32', 33'. The frames are guided along a structure 34 comprising two guide beams 35 and 36. The frame comprising props 28 and 29 is guided along the outer side of the guide beam 35 by means of a slide 37 hinged to the coupling beam 32, and the frame comprising props 30 and 31 is guided along the inner side-of the guide beam 36 by means of a slide 38 hinged to the coupling beam 33. The frame comprising props 28' and 29 is guided along the inner side of the guide beam 35 by means of a slide 37 hinged to the coupling beam 32' and the frame comprising props 30' and 31' is guided along the outer side of the guide beam 36 by means of a slide member 38' hinged to the coupling beam 33.

The frame comprising props 28 and 29 is coupled to the frame comprising props 28' and 29' by means of an endless rope 39, which passes over wheels 40 and 41 carried in bearings in the guide beam 35, and is fastened to the slides 37 and 37'. The frame comprising props 30 and 31 is coupled to the frame comprising props 30' and 31' by means of a rope 39, which passes over wheels 40' and 41' carried in bearings in the guide beam 36, and is fastened to the slides 38 and 38 of the two frames.

The structure 34 comprises a cylinder 42; the end 44 of the piston rod 43 of the said cylinder is provided with two wheels .45. A rope 46,is fastened to the cylinder at 47 and passes, via one of the wheels 45, and via wheels 48 and 49 carried in hearings in the structure, through the guide beam 35 to the conveyor 50, to which it is fastened at 51. A second rope, 46', is fastened to the cylinder at 47' and passes, via the other wheel 45, and wheels 48' and 49 carried in bearings in the structure, through the 6 guide beam 36 to the conveyor, to which it is fastened at 51'.

The frames are provided with spring loaded plungers 52-55 and 52'55' which ride in contact with the guide beams 35 and 36.

Between the frames a piston and cylinder unit 56-57 is provided which serves periodically for advancing the conveyor. The cylinder 56 is fastened to the ends 59 and 59' of the guide beams 35 and 36 by means of chains 58 and-58', so that it possesses a certain degree of mobility. As a result, the cylinder cannot affect the position of the structure 34, and the piston rod 57 cannot be subjected to a bending load. To prevent the cylinder from being displaced vertically, it is provided with lugs 60 which have bifurcated ends for receiving the ends 59 and 59' of the guide beams.

When the support has to be shifted, the props of the hindmost frames (in the drawing the frames comprising props 28'31') are released and pressure is admitted to cylinder 42. The structure 34 is pushed forward along the guide beams 35, 36 over a distance which is twice as long as the stroke of the piston 43. The wheels 40 and 40 are also moved over the said distance, and pull the released frame forwards over a distance which is four times as long as the stroke of the said piston. Subsequently, the props 28'31' are reset.

The ropes 46 and 46' are of equal length so that the two ropes are under equal stress when the structure 34 is correctly disposed. The spring loaded plungers cause the release-d frames to become correctly disposed when they are shifted. If a deviation has occurred, the rope which is fastened to the conveyor at the point where the support is nearest to the conveyor will be slacker than the rope fastened at the other side of the conveyor. When the ropes are tightened owing to pressure having been admitted to cylinder 42, the rope fastened at the side where the distance between the support and the conveyor is largest will be drawn taut first. While being shifted, the structure will consequently be turned in such a way that the two ropes are subjected to the same tensile force, so that the structure will be correctly disposed.

In the embodiment shown in FIGURE 7, which is similar to that shown in FIGURE 1, a laminated spring 62, 62', is fastened to each of the slides by means of bolts 61 and 61' respectively. The ends of the springs are provided with pressure pieces 26-27 and 26'27, respectively, which lie against or are connected to the outer sides of the frames. If space permits, these laminated springs can alternatively be located at the insides of the frames. The length of the laminated springs is such that the pressure pieces exert a pressure on the frames near the props 2-3 and 2'3', respectively. The length of the arm of the moment, and consequently also the magnitude of the moment exerted by the springs at a given tension, is then maximum. During the shifting of a supporting frame relative to the guide structure 8 the pressure pieces do not slide in contact with the said structure or any other part, so that no extra friction is produced which would increase the force required for the shifting.

In the embodiment shown in FIGURE 8 the spring plungers 26-27, and 26'27, respectively, are provided with stops 63 and 63', respectively, which limit the movement of the plungers under their springs so that these cannot project from the frames by more than the spacing which obtains between the frames and the guide structure at the locations of the plungers when the frames are parallel to such structure. If a released support frame is positioned at an angle to the central guide structure, the plunger located at that side of the pivot where the distance between the frame and the central structure is larger than normal therefore lies clear of the guide structure, whereas the plunger at the other side of the pivot is pressed against the structure by the plunger spring. As a result, a force which tends to turn the frame into a position parallel to the central structure is exerted on the frame on one side of the pivot.

The plunger stops may be fitted in such a way that the pressure members normally lie slightly clear at the guide structure, so that, when the support frames are in their normal positions parallel with the guide structure, the plungers do not give rise to any frictional restraint on the sliding movement of the frames. If the central guide structure is turned through a small angle relative to a fixed frame only, one of the plungers of that frame presses against the guide structure. Thus if frame 1 is turned anticlockwise in respect of FIGURE 8, the plunger 26 will be pressed against the guide structure, whereas the plunger 27 will move away from it. Spring 62 will then exert a corrective force on the frame 1. If the springs have been fitted in pre-stressed conditions, even a small angular displacement of the frame will cause the springs to exert a sufficient force for restoring the frame to centralised position when it is released.

'On the left hand side of FIGURE 8, a leaf or laminated spring 62', pushes the plungers 26' and 27 towards the guide structure 8. This spring is fastened to the slide 21. The plungers 26', 27 are provided with stops 63', which may be so arranged that they just clear the guide structure when the frame 1 is parallel to it. If the frame is slightly turned anticlockwise in the aspect of FIGURE 8, with respect to the central structure, the plunger 26' is retained out of contact with the structure 8, by the stop 63', whereas the plunger 27' is pressed against the structure by the spring 62. This spring consequently tends to turn the frame back to the correct position.

When the guide structure is shifted along a line which is at an angle to the frame which is for the time being fixed, one plunger will slide along the guide structure and impose some frictional resistance. However the plungers can be arranged so as to bear against the runner portions 64 and 64 of the slides 21 and 21', respectively. This has the advantage that, even if a fixed frame is angled with respect to structure 8 while this is being shifted the loaded plunger does not produce additional friction. In that case, however, the length of the leverage arm exerting the turning force will be somewhat smaller.

This can be amply compensated for, however, by fitting the springs in a sufficiently pre-stressed condition. Alternatively or in addition, the runners 64 and 64 may be made longer than is required for ensuring a good guiding action so that the plungers can be located at greater distances from the frame pivots.

We claim:

1. A support assembly for use with a face conveyor, the latter being of the type arranged to be disposed parallel with the face of a mine having a floor and roof, said support assembly comprising a horizontally extending guide structure, means operatively connected with said guide structure and adapted to be connected to the face conveyor for effecting a horizontal advancing movement of said guide structure toward the face conveyor by a force transmitted to the guide structure such that the guide structure when in a proper position of angular and transverse alignment with a predetermined fixed point on the face conveyor maintains such proper position of alignment during its advancing movement and when out of such proper position of alignment tends to move toward such proper position of alignment during its advancing movement, first and second horizontally elongated prop means arranged to be disposed in properly aligned positions parallel with respect to each other and each adjacent a separate side of said guide structure when the latter is disposed in its proper position of alignment, each of said prop means being extendible for rigid interengagement with the floor and roof and retractable for horizontal advancing movement along the floor, means for connecting each of said prop means with said guide structure for relative horizontal movement with respect thereto and for relative horizontal angular movement with respect thereto, means for effecting a horizontal advancing movement of one of said prop means when retracted with respect to the other of said prop means when extended during the advancing movement of said guide structure, and means for maintaining the advancing retracted prop means in angular alignment with said guide structure and for yieldingly permitting angular movement of the latter with respect to the extended prop means when the latter is out of its proper aligned position during the advancing movement of said guide structure as a result of the tendency thereof to move toward its properly aligned position so that the position of the nonaligned extended prop means when subsequently retracted and advanced will be more nearly in its proper position of alignment.

2. A support assembly as defined in claim 1 wherein each pr-op means includes a pair of vertically extending props having means on the ends thereof for engaging the floor and roof respectively, and means interconnecting said props permitting articulation in a vertical plane.

3. A support assembly as defined in claim 1 wherein said means for maintaining and yieldingly permitting angular movement comprises spring members acting on each of said prop means for elastically resisting the angular movement of the associated prop means out of its proper aligned position.

4. A support assembly as defined in claim 3 wherein said means for maintaining and yieldingly permitting angular movement further comprises means mounting said spring members so as to exert forces on the associated prop means only while the latter is out of its proper aligned position.

5. A support assembly as defined in claim 3 wherein said means for maintaining and yieldingly permitting angular movement further includes stop means for retaining said spring members in prestressed condition.

6. A support assembly as defined in claim 1 wherein said connecting means comprises a pair of parallel guide tracks carried by said guide structure and a runner mounted for sliding movement along each of said guide tracks and pivotally connected to the associated prop means about a vertical axis disposed intermediate the ends of the latter.

7. A support assembly as defined in claim 6 wherein said means for maintaining and yieldingly permitting angular movement includes a pair of horizontally spaced spring members acting between each prop means and the associated side of said guide structure, the vertical pivotal axis of each prop means being disposed between the associated pair of spring members.

8. A support assembly as defined in claim 6 wherein said means for maintaining and yieldingly permitting angular movement includes a leaf spring assembly associated with each prop means, the central portion of each leaf spring assembly being secured to the associated runner and having opposite end portions bearing against the associated prop means in spaced relation to the associated vertical pivotal axis thereof.

9. A support assembly as defined in claim 1 wherein said guide structure movement effecting means comprises a flexible haulage member.

10. A support assembly as defined in claim 9 wherein said guide structure movement effecting means further comprises guide means carried by said guide structure for guidingly receiving said flexible haulage member.

11. A support assembly as defined in claim 10 wherein said guide means comprises a pair of guide wheels.

12. A support assembly as defined in claim 1 wherein said prop means movement effecting means comprises flexible tie means connected to both of said prop means and mounted for displacement in response to the advancing movement of said guide structure to cause movement of a retracted prop means simultaneously with the movement of said guide structure.

13. A support assembly as defined in claim 11 wherein said guide structure comprises two parallel guide beams and wherein each of said prop means includes a prop unit associated with one side of each of said guide beams.

14. A support assembly as defined in claim 13 wherein said prop means movement effecting means comprises an endless flexible tie member associated with each guide beam connected to the prop units associated therewith and mounted for bodily displacement in response to the advancing movement of said guide structure to cause movement of a released prop unit simultaneously with the movement of said guide structure.

15. A support assembly as defined in claim 13 wherein said guide structure movement effecting means comprises two flexible haulage members adapted to be connected to the face conveyor at points spaced therealong, and a haulage gear for displacing said flexible members.

16. A support assembly as defined in claim 15 including a piston and cylinder unit connected to said guide means and adapted to serve for advancing the face conveyor.

17. A support assembly as defined in claim 16 wherein said piston and cylinder unit is connected to said guide structure by elongated flexible means.

References Cited UNITED STATES PATENTS OTHER REFERENCES German application Das. 1,102,679, 1961.

DAVID J. WILLIAMOWSKY, Primary Examiner. JACOB SHAPIRO, Examiner. 

1. A SUPPORT ASSEMBLY FOR USE WITH A FACE CONVEYOR, THE LATTER BEING OF THE TYPE ARRANGED TO BE DISPOSED PARALLEL WITH THE FACE OF A MINE HAVING A FLOOR AND ROOF, SAID SUPPORT ASSEMBLY COMPRISING A HORIZONTALLY EXTENDING GUIDE STRUCTURE MEANS OPERATIVELY CONNECTED WITH SAID GUIDE STRUCTURE AND ADAPTED TO BE CONNECTED TO THE FACE CONVEYOR FOR EFFECTING A HORIZONTAL ADVANCING MOVEMENT OF SAID GUIDE STRUCTURE TOWARD THE FACE CONVEYOR BY A FORCE TRANSMITTED TO THE GUIDE STRUCTURE SUCH THAT THE GUIDE STRUCTURE WHEN IN A PROPER POSITION OF ANGULAR AND TRANSVERSE ALIGNMENT WITH A PREDETERMINED FIXED POINT ON THE FACE CONVEYOR MAINTAINS SUCH PROPER POSITION OF ALIGNMENT DURING ITS ADVANCING MOVEMENT AND WHEN OUT OF SUCH PROPER POSITION OF ALIGNMENT TENDS TO MOVE TOWARD SUCH PROPER POSITION OF ALIGNMENT DURING ITS ADVANCING MOVEMENT, FIRST AND SECOND HORIZONTALLY ELONGATED PROP MEANS ARRANGED TO BE DISPOSED IN PROPERLY ALIGNED POSITIONS PARALLEL WITH RESPECT TO EACH OTHER AND EACH ADJACENT A SEPARATE SIDE OF SAID GUIDE STRUCTURE WHEN THE LATTER IS DISPOSED IN ITS PROPER POSITION OF ALIGNMENT, EACH OF SAID PROP MEANS BEING EXTENDIBLE FOR RIGID INTERENGAGEMENT WITH THE FLOOR AND ROOF AND RETRACTABLE FOR HORIZONTAL ADVANCING MOVEMENT ALONG THE FLOOR, MEANS FOR CONNECTING EACH OF SAID PROP MEANS WITH SAID GUIDE STRUCTURE FOR RELATIVE HORIZONTAL MOVEMENT WITH RESPECT THERETO AND FOR RELATIVE HORIZONTAL ANGULAR MOVEMENT WITH RESPECT THERETO, MEANS FOR EFFECTING A HORIZONTAL ADVANCING MOVEMENT OF ONE OF SAID PROP MEANS WHEN RETRACTED WITH RESPECT TO THE OTHER OF SAID PROP MEANS WHEN EXTENDED DURING THE ADVANCING MOVEMENT OF SAID GUIDE STRUCTURE, AND MEANS FOR MAINTAINING THE ADVANCING RETRACTED PROP MEANS IN ANGULAR ALIGNMENT WITH SAID GUIDE STRUCTURE AND FOR YIELDING PERMITTING ANGULAR MOVEMENT OF THE LATTER WITH RESPECT TO THE EXTENDED PROP MEANS WHEN THE LATTER IS OUT OF ITS PROPER ALIGNMENT POSITION DURING THE ADVANCING MOVEMENT OF SAID GUIDE STRUCTURE AS A RESULT OF THE TENDENCY THEREOF TO MOVE TOWARD ITS PROPERLY ALIGNED POSITION SO THAT THE POSITION OF THE NONALIGNED EXTENDED PROP MEANS WHEN SUBSEQUENTLY RETRACTED AND ADVANCED WILL BE MORE NEARLY IN ITS PROPER POSITION OF ALIGNMENT. 